Physicians' Health Study

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government.
Read our disclaimer for details.

To assess the effect on cardiovascular mortality of alternate-day consumption of 325 milligrams of aspirin and, secondarily, the effect on cancer incidence of alternate-day consumption of 50 milligrams of beta-carotene.

Thrombosis plays a major role in the late stages of coronary occlusion. Platelet aggregation is a large component in the formation of arterial thrombi. In pharmacologic studies, aspirin has been shown to inhibit platelet aggregation and, therefore, might be expected to prevent coronary occlusion. These effects are apparent in the dose range of l00-l000 mg/day, and may be most evident at l60 milligrams daily. Higher doses seem to be no more effective in either inhibition of platelet agreeability or prolonged bleeding time.

Although an early case-control study by Jick and Miettinen showed a large benefit, most observational studies had shown a cardiovascular benefit of about 20 percent. Conclusive data could only result from a randomized trial with a large sample size.

DESIGN NARRATIVE:

Randomized, double-blind, fixed sample. Participants were randomized into one of four treatment groups: one 325 milligram aspirin tablet every other day, alternating with one 30 milligram capsule of beta-carotene; one aspirin every other day, alternating with one capsule of beta-carotene placebo; one aspirin placebo tablet every other day, alternating with one capsule of beta-carotene; and one aspirin placebo tablet every other day, alternating with one capsule of beta-carotene placebo. Major endpoints for the cardiovascular component of the study were cardiovascular mortality, total mortality, and coronary events.

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Ages Eligible for Study:

40 Years to 84 Years (Adult, Senior)

Sexes Eligible for Study:

Male

Accepts Healthy Volunteers:

No

Criteria

Male physicians, ages 40 to 84. No history of stroke, myocardial infarction, cancer, or renal disease. No contraindications to aspirin or beta-carotene. No current usage of aspirin or Vitamin A tables greater than once per week.